1. Field of the Invention
This invention relates to a road embedded light reflecting traffic marker, and particularly to an elevated light reflecting surface, that on impact, temporarily retracts into the marker housing and beyond harms way and immediately thereafter is restored to its elevated light reflecting position by pneumatic action.
Particularly with the advent of the automobile, various markers to delineate onward and return travelling portions of a highway have been conceived and implemented. Simplistically, one paints the road surface with white, yellow, or other colored lines.
In night conditions and more particularly in fog or with wet surfaces, such delineation is difficult to see unless illuminated either upon or within or the delineation is retro-light reflective; that is, reflects light essentially back to the source (sic. for an oncoming vehicle with head lamps on, light is reflected to the region from whence the light came; hence, visible light is reflected to the driver of the oncoming vehicle).
Thus, in order of overcome the foregoing in some applications, elevated markers, permanently or temporarily placed onto the travelling surface, or even adjacent thereto, delineate traffic flows.
The road embedded elevated reflectors have found great application in temperate climates where accumulations of light obscuring materials, such as snow, do not tend to accumulate over and to cover the retro-light reflective surface of such markers.
A typical retro-light reflective unit presently used in the moderate climates of North America (Georgia, Florida) is one manufactured by Amerace Corporation of Illinois, U.S.A. under the trade marks LIFE-LITE (trademark) by STIMSONITE (trademark). It is available in various colors. This light reflective reflector is hard mounted onto the rigid travelling surface portion of the road, whether that surface be asphalt or concrete. So long as sand, slush, and snow do not accumulate to a depth greater than that of the effective height of the reflective unit, about 2 cm., the reflective surfaces effectively reflect light at night. These particular units are generally secured to their surround directly, either mechanically or by an appropriate adhesive or bonding means; or, with the aid of an intermediate holder, which is affixed, appropriately, into the road surface, while the light reflective element is removably attached to the holder. In these temperate climates, where snow and slush and other road accumulations are not a problem, hard mounted traffic delineators as aforesaid have had stupendous commercial success.
Hard mounted reflector units, as aforesaid, are not totally satisfactory in less temperate climates when road clearing devices such as snow plows, or road graders, are used to scrape off any accumulations from the surface of the road. Such scraping generally pulls the hard mounted reflector unit, and/or the reflector, out of the road surface and in most cases also rips away subjacent and adjacent surface road material. Not only is the reflector itself destroyed or damaged so as to require replacement, but as a prerequisite, the road surface material ripped away must be restored. If an intermediate holder is used for the reflector, it generally is likewise damaged and requires replacement.
Thus, these devices are not cost effective where plowing is necessary to maintain the road clear as in winter where snow or slush accumulate.
Attempts over the years to make a commercially viable traffic marker whose light reflective surfaces are above grade (above the hard surface of the road), yet will not be damaged by plow, scraper and the like, and avoid costly road repair maintenace, or danger to snow plow operators, have generally been marginal at best.
For example, presently commercially available is a hard mounted traffic delineator with an elevated light reflective surface or lens. This lens is protected, on either side thereof, by shallow tapered planes extending both fore and aft; the planes acting as guides for the snow plow blade and the like so as to elevate the blade over the traffic marker while the blade travels over the marker as means to avoid the blade edge striking the light reflective surface and damaging the same. Superficially, such units, known as LIFE-LITE 96 (trademark) by the aforesaid Amerace Corporation appear to satisfy the demand for a plowable pavement marker. However, when the snow turns to slush, as a result of salting of the roads, salt builds up in the various crevices of such markers and obscures the light reflective lens whereupon during that duration the particulate remains accumulated on the light reflective lens, rendering it effectively non-light reflective at night. More importantly, however, during snow plowing, if perchance the surface of the road is slightly glazed with ice, typical conditions as exist through the upper midwestern United States of America and Canada, the snow plow operator will lose control because of this impact. There have been reports of snow plow operators actually being injured and equipment overturned and destroyed because of the basic failure of such units to be free of any resistance to snow plow blade impact. Such conditions cannot be tolerated particularly when it is appreciated that a snow plow out of control not only is unsafe to the snow plow driver, but to oncoming and following traffic. The aforesaid is a laudable although unsuccessful attempt to overcome the prior art in producing a plowable traffic delineator that disposes its light reflective surface at an elevation above the surface of the road, for it is well known in the art that light reflective surfaces above grade are superior to the painting of lines or to any other on surface demarcations whether they contain low or high degrees of light reflective properties. Any highway authority in North America recognizes that.
2. Description of the Prior Art
Of relevance, therefore, to this invention are three prior art retractable traffic delineators, all of which have failed to achieve any commerical success.
Krebs, U.S. Pat. No. 2,073,968 issued Mar. 16, 1937 entitled "Highway Marker", discloses a partially road embedded retractable traffic marker with an elevated light reflective element housed on a bottom or holder that is biased by the subjacent spring while held in its housing. It, however, has no protective ramps or guides to protect the light reflective element from scraping action as would occur by a snow plow blade and the upper portion of the housing is above grade and hence is incapable of responding to plowable conditions without damage.
Converso, U.S. Pat. No. 3,257,552 issued June 21, 1966, entitled "Flush Lamp Mounting Device", discloses a retractable traffic delineator whose light projecting element, in fact, is not retro-reflective, but rather the delineator itself contains a source of illumination surrounded by a protective plate which retracts simultaneously with the light source into the retractable traffic delineator. The internal housing of this device is open beneath so as to permit electrical conducting wires to exit the unit and to travel to a source of energy by which the light within the unit may be illuminated. Water seepage into the marker occurs through the aperture. Further, the resilient ring used is bonded to its adjacent body parts and under insite conditions, the bonding breaks down after frequent cyclical retractions and the unit is destroyed.
Kone, U.S. Pat. No. 3,292,506, entitled "Flush Lamp Mounting Device", discloses the flexible membrane with its upper surface in elevation subjacent to the upper surface of the marker housing. This provides an annular plenum for accumulation and adhere onto the light reflective surfaces. Further, the base aperture allows water to seep into the unit which in winter freezes, rigidifying the coil spring and inhibiting retractability when it is most needed.